1. Field of the Invention
The present invention relates to a thermosiphon for efficiently transferring heat by taking advantage of phase change in a working fluid.
2. Description of the Related Art
One of Conventional thermosiphons of this kind is disclosed in, for example, Japanese un-examined patent publication No. 2001-33139. The thermosiphon comprises: a condensing section (a condenser) attached to a Stirling refrigerator (a refrigerator); and a circulation path consisting of a liquid line (a liquid pipe), an evaporator section (an evaporator) and a gas line (a gas pipe), said circulation path being connected to said condensing section.
Operating the Stirling refrigerator deprives the condensing section of heat to thereby condense a refrigerant (a working fluid) thereinside, then supplying the refrigerant thus condensed to the evaporator section via the liquid line so as to vaporize the fed refrigerant inside the evaporator section, thereby depriving a surrounding therearound of heat as a vaporizing latent heat, so that the heat around the evaporator section is transferred to the condensing section and further to the Stirling refrigerator by returning the vaporized refrigerant to the condensing section via the gas line.
For the above-mentioned condensing sections, those which are manufactured by machining metal ingots or by drawing metal plates have conventionally been known other than the one in the form of a coiled copper pipe as described in the above-mentioned patent publication. Further, for the above-mentioned evaporator sections, those which are manufactured by roll bond method or the like have been known besides the one in the form of a zigzagged copper pipe described in the above-mentioned publication.
According to the conventional thermosiphons, however, condensers formed by coiling a copper pipe have had a problem that it is difficult to keep such condensers in close contact with the refrigerators. Further, condensers manufactured by machining process or the like have had a problem that a high precision processing is necessary to keep such condensers in close contact with the refrigerators, thus resulting in high manufacturing costs.
On the other hand, evaporators formed of copper pipes have had a problem that as the cooling of the surroundings around the evaporators progresses, condensed working fluids are likely to stay inside the evaporators, thus leading to a possibility that circulation paths are clogged. Whilst evaporators manufactured by the roll bond method have had no problems as long as working fluids such as chlorofluorocarbon (CFC), alternatives to CFC or the like are used, they have had a problem that it eventually is impossible to use such evaporators as they are unable to withstand an inner pressure if other working fluid, such as carbon dioxide is used in line with no-CFC policy.
Accordingly, it is an object of the present invention to provide a thermosiphon that can be easily manufactured at low manufacturing costs, and at the same time having an excellent pressure withstanding property, by solving the above-mentioned problems.
It is another object of the present invention to provide a thermosiphon in which the circulation of a working fluid is not hindered.
To attain the objects, there is proposed a thermosiphon in accordance with a first aspect of the present invention, comprising: a condenser attached to a refrigerator for condensing a working fluid; a liquid pipe for discharging the working fluid condensed in the condenser; an evaporating pipe for vaporizing the working fluid fed from the liquid pipe in order to deprive an inside of a container of heat; and a gas pipe for returning the working fluid vaporized inside the evaporating pipe to said condenser, wherein said condenser is made up of: a condensing section made of an extruded member where a plurality of fine pores are formed; a branching section provided on an upstream side of the fine pores of the condensing section to supply the gaseous working fluid returned from the gas pipe to each of the fine pores of the condensing section; and a colleting section provided on a downstream side of the fine pores of the condensing section to collect the working fluid condensed in the fine pores of the condensing section and then supply the working fluid into the liquid pipe, and wherein the gas pipe is connected to an upper portion of the branching section while the liquid pipe is connected to an lower portion of the collecting section.
According to the construction of the first aspect of the present invention, the condensing section made of an extruded member is bent to conform to a contour of the refrigerator and is provided at both ends thereof with the branching and collecting sections, so that the condenser is formed. After the gaseous working fluid is introduced from the gas pipe into a plurality of the fine pores of the condensing section through the branching section, the gaseous working fluid is condensed in the fine pores to merge in the collecting section and then it is introduced into the liquid pipe. Further, as the gas pipe is connected to the upper portion of the branching section and the liquid pipe to the lower portion of the collecting section, the working fluid condensed inside the collecting section can be fed out of the liquid pipe and at the same time the working fluid condensed inside the branching section can be fed into the fine pores without flowing back to the gas pipe.
A thermosiphon according to a second aspect of the present invention is the one according to the first aspect, further including a clamping member for bringing the condensing section into close contact with an endothermic portion of the refrigerator, and such clamping member is provided along an outer periphery of the condensing section.
According to the construction of the second aspect of the present invention, the condensing section is allowed to closely contact the endothermic section of the refrigerator.
Further, a thermosiphon according to a third aspect of the present invention comprises: a condenser attached to a refrigerator for condensing a working fluid; a liquid pipe for discharging the working fluid condensed in the condenser; an evaporator for vaporizing the working fluid fed from the liquid pipe in order to deprive an inside of a container of heat; and a gas pipe for returning the working fluid vaporized inside the evaporator to said condenser, wherein said evaporator is made up of: an evaporating section formed of an extruded member, having a plurality of fine pores formed substantially in parallel with one another; an introducing section provided on an upstream side of the fine pores of the evaporating section, said introducing section introducing the liquid working fluid fed from the liquid pipe into the fine pores of the evaporating section; and an exhausting section provided on a downstream side of the evaporating section, said exhausting section collecting the evaporated working fluid in the fine pores of the evaporating section and then supplying the working fluid thus collected into the gas pipe, and wherein said evaporating section is provided along an outer periphery of the container.
According to the construction of the third aspect of the present invention as described above, the evaporating section made of an extruded member is suitably bent while the introducing section and the exhausting section are provided on both ends thereof, so that the evaporator is formed. After the working fluid condensed in the condenser is introduced from the introducing section of the evaporator into the fine pores of the evaporating section via the liquid pipe, the working fluid is evaporated by depriving the surroundings of the evaporator of heat, as vaporizing latent heat inside the fine pores, which is then allowed to merge in the exhausting section and then discharged into the gas pipe. As the evaporating section is provided along the periphery of the container, the container can be efficiently cooled from its peripheral side.
A thermosiphon according to a fourth aspect of the present invention is one in which a plurality of the fine pores of said evaporator are arranged vertically, disposed in an approximately horizontal manner.
According to the construction of the fourth aspect of the present invention, a liquid working fluid is comparatively unlikely to collect in the upper fine pores, so that if the lower fine pores are clogged by the liquid working fluid, a gaseous working fluid can bypass the lower fine pores to flow through the upper fine pores, thus preventing the circulation of the working fluid from being hindered inside the fluid path.